Even in a state like Colorado, where cowboys remain kings and bears still stop traffic, Western art must lasso its own place in the cultural landscape. A major museum has to work hard to build a collection of century-old mountain sunrises and desert sunsets, especially when it’s the modern and contemporary galleries that get all the attention these days.

But the Denver Art Museum has made Western art its mission, and stuck to it. DAM is the only major museum in the country to have a department dedicated solely to the genre and it has given over serious square footage for the display of Frederic Remington, C.M. Russell and other legends. The in-house Petrie Institute of Western American Art, founded in 2007, has strengthened the effort with scholarly research on the painters and sculptors who have made the region their muse, building an endowment of about $7 million.

All that work paid off like a gold strike last week when local businessman and collector Henry Roath officially handed over 50 of his prized possessions to the museum. The gift added nearly 10 percent to DAM’s collection, which has been growing in bits and pieces for a dozen years.

But it doubled its importance overnight.

Roath, a retired lawyer and banker, is a picky and focused collector. He didn’t just acquire a Thomas Moran, he bought Moran’s “Sunset, Green River Butte,” a glowing 1916 landscape that may be the revered painter’s best effort. He didn’t purchase any old Ernest Blumenschein, he got the 1920 treasure “Landscape with Indian Camp.”

“That’s one of the great moments in that collection and it certainly will be important to Denver’s holdings,” said Andrew Walker, director of the Amon Carter Museum of American Art in Fort Worth, Texas, which has its own much-admired collection.

The Roath pieces have actually been on loan to DAM since 2011, as a sort of run-up to the donation, so the strength they add is already evident on the museum’s walls. The collection runs particularly strong in Southwestern art.

“There is at least one major work by every member of the Taos Society,” said Thomas Smith, who directs the Petrie Institute and is overseeing the transfer and display of the new additions.

The Taos Society, which gathered in Taos for a decade starting in 1915, was known for capturing local landscapes and culture through a framework that combined both formal and indigenous traditions, and for putting New Mexico on the international art map. It was instrumental in introducing Indian cultures, in a dignified way, to the national population.

Among its members’ pieces now in DAM’s hands: E. Irving Couse’s “Moonlight in Taos,” a painterly depiction of an Indian reclining under a full moon, Oscar E. Berninghaus’ “Indians Threshing Wheat,” and W. Herbert Dunton’s crowd-pleasing “Black Bears.” There are six works by Joseph Henry Sharp.

But the Roath gift is broad and includes three-dimensional works, too. There are two editions of Remington’s bronze “The Broncho Buster,” including the rare “Wooly Chaps” version, as well as the rider-on-horse “Pursued,” by Alexander Phimister Proctor, whom Smith praises as “the most important artist to come out of Denver.”

There are two paintings each from Charles Patridge Adams, Albert Bierstadt, E. Martin Hennings, William Herbert Dunton and Maynard Dixon, plus important solo pieces from Walter Ufer, Thomas Hart Benton and George deForest Brush.

That Roath focused on attaining one or two exceptional works by the West’s biggest stars makes his gift “a perfect match for a museum,” which is interested in holding high-quality paintings it can display, rather than owning multiples that end up in storage, according to Smith.

And that DAM has worked so hard to establish its Western art credibility makes the gift logical. Collectors often hope to park their wares somewhere at the end of their run and they need a repository, like DAM, that has proven its scholarly intentions by issuing a major publication every year, and that has achieved a level of financial stability they can trust. It helps that the museum gets a million-plus visitors a year, guaranteeing the work will be seen.

That makes it attractive to a guy like Roath, who grew up in Denver and attended East High School and the University of Colorado in Boulder. He’s been a member of the Petrie’s advisory board since 2005 and knows the operation well.

For DAM, which considers regional collecting part of its mission, a decade of careful museum strategy has paid off. Prior to 2001, it had just “a handful” of Western works, Smith said. Now it has 600. With Roath’s masterworks in the mix it can begin trading off its lesser pieces to expand the collection’s geography, perhaps into far West works from California painters.

There’s a benefit for local museumgoers as well. A higher level of quality makes for a better experience. These works don’t just record the region’s romanticized past, or tell the story of people who lived here for millennia, they also serve as fine examples of what an artist can do with a brush, or the precision he can freeze in bronze.

“Judas,” a new novel by Amos Oz, is a paradox of stillness and provocation. The Israeli author, a long-rumored contender for the Nobel Prize, has reduced the physical action of this story to a tableau of domestic grief.